1. Field of the Disclosure
The present disclosure relates generally to electrophotographic imaging devices such as a printer or multifunction device having printing capability, and in particular, to laser scanning systems employing multiple light sources.
2. Description of the Related Art
Electrophotographic image forming devices typically form images by scanning light across the surface of a photoconductive surface. Typically, a video signal causes a light source, such as a laser or laser diode, to pulse on and off as its laser light scans across the surface of the photoconductive surface. Those select portions of the photoconductive surface that are exposed to the laser light are electrically discharged thereby forming a latent electrostatic image. A charged developer material, such as toner, is brought into contact with the photoconductive surface by a developer roller such that the charged toner attaches to the discharged areas of the photoconductive surface. The toner on the photoconductive surface is then transferred onto a recording medium, such as a media sheet or a transfer belt for subsequent transfer to a media sheet.
Typically, the video signal is produced by an integrated circuit, such as an application specific integrated circuit (ASIC), and transmitted over an electrical conductor to a laser driver which in turn drives the light source based on the video signal. In laser scanning systems, most especially in laser color printers, it is common practice to utilize multiple light sources that are driven by one or more laser drivers to form latent images on the photoconductive surface. The ASIC produces multiple video data signals that are simultaneously sent over several parallel channels to control each unique light source. For example, as shown in FIG. 1 illustrating an 8 laser system, there may be eight different video data signals DATA1 to DATA8 transmitted over eight separate channels 5 to multiple laser drivers 7 to control eight different laser diodes 9. In this case, a single channel 5 is dedicated to carry video data for a single laser diode 9.
The use of multiple light sources may improve the overall throughput of the imaging apparatus. However, implementing such configuration, where the number of unique signals for communicating video information to the multiple laser diodes would require an increase in the channels over which the unique signals are transmitted, results in higher manufacturing costs. Power dissipation may also increase due the increased number of channels. Additionally, as more light sources are used, more interfaces would be required which occupy relatively large portions of valuable silicon area in both the ASIC and the laser drivers. Moreover, the additional channels used to accommodate connections between the interfaces may increase the overall size of circuitries within the laser scanning system.
Accordingly, there is a need for a solution to more efficiently communicate video information in scanning systems implementing multiple light sources.